Capacitor with grounded plates mounted on cooling pipes



Oct. 25, 1949. H. c. DUSTMAN 2,485,131 7 CAPACITOR WITH GROUNDED PLATES MOUNTED on COOLING PIPES Filed Dec. 2 Sheets-Sheet 1 Filed Dec. .21, 1945 -Oct. 25, 1949. v H. c. DUSTMAN 2,436,131

CAPACITOR WITH GROUNDED PLATES MOUNTED 0N COOLING PIPES 2 SheetsQShe'et dA/g' 2 27 Patented Oct. 25, 1949 "UNITED STATES PATENT OFFICE CAPACITOR WITH GROUNDED PLATES MOUNTED ON COOLING PIPES Herman C. Dustman, West Allis, Wis., .assignor to Allis-Chalmers Manufacturing Company, .Milwaukee, Wis., a corporation of Delaware Application December 21, 1945, Serial No. 636,462

1 Claim.

plates, the heat must be transmitted through the dielectric to the wall of 'the capacitor casing or'to a cooling device disposed Within the casing. The

temperature of the dielectric is then nonuniform and'the continuous rating of thecapacitor is restricted by the necessity of limitingthe temperature' of the dielectric at its hottest spot.

'- The' above mentioned disadvantage may be avoided by utilizing-the plates themselves or parts thereof as heat collecting-elements. When the plates are rigid, 'theplates of one polarity may be mounted on at least one metallic pipe in thermally conductive relation therewith, and heat "may be abstracted'therefrom by causing a flow of'cooling fluid through the pipe. -When feasible,

. it is convenient to--.conductively connect the set of plates so provided with the casing, so as to avoid .thenecessity of insulating the elements of the cooling system from'the casing. To reduce the .cost and bulk of. the capacitor to a minimum it is advantageous to utilize plates having a gen- .erallysquare outline and having substantially all the same configuration, the plates of one polarity being rotated by ninety degrees with respect to the plates of the other polarity to permit mounting the two sets of plates on their respective supports.

It is therefore an object of the present invention to provide a capacitor of the rigid plate type in which heat evolved in a solid or liquid dielectric is removed therefrom through at least one of the sets of plates of the capacitor.

Another object of the present invention is to provide a capacitor of the rigid plate type in which an element serves both as a support for a set of plates and as cooling element for the capacitor.

Another object of the present invention is to provide a capacitor of the rigid plate type in which both sets of plates consist substantially entirely of elements having a square outline and a uniform configuration.

Objects and advantages-other than those above setforth will be apparent from a consideration of the followingdescription-when readin connection .Wlth the accompanying drawing, in which,

Fig. 11s a view in longitudinal cross-section through one embodiment of thepresent inventionhaving a set of grounded plates and a set of .platesto be placed under potential;

. Fig. 2 is a viewin transverse cross-section taken along line II--II in Fig. 1, a portion of the capacitor elements being assumed removed to show one of the connections for the set of plates under potential Fig.-3-is a partial'view in-horizontal crosssection: taken along line IIIIII in'Fig. 2;

Fig. 4 is a view inelevationof one of the end 'plates of the set-under potential;

Fig. 5 is a view in elevationof oneof the grounded plates Fig.6 is a view in elevation of one of the intermediate plates of the'set'under potential; and

'Fig. 7 isanenlarged partial viewinlongitudinal cross-section taken along line VIIVII in'Fig. 2. Referring'more particularly-to the drawing by characters of reference, numeral designates the side walls ofa parallelepipedic casing, which are preferablymade from a single sheet of a suitablemetal, such as copper.

The top and bottom edges of walls H are preferably bent to 'rial 14' suchas mineral oil.

The plates of "the capacitor are suspended from cover l2 through a pair of hangers'lE. Each hanger consists of a brass plate having its edges bent atninety degrees to form flanges and is 'fastened'to cover l2 by means of brass boltsl6.

The plates to be placed under potential comprise a plurality of parallel intermediate plates 11 'of suitable rigid sheet metal such as aluminum.

Plates l 1 are of generally square outline provided with a plurality of circular apertures l8 for mounting the plates on common rod-like supports. The edges of plates'l'l are provided with a plurality of indentations IQ of substantially larger size than apertures l8 for providing space for the supports carrying-the grounded set of plates. Plates H are assembled between tWo end plates 21 identical to plates l1 except for additional indentations 22 for providing space for mounting elements associated with the plates.

Plates 2| are disposed vertically and rest on one or more horizontal copper pipes 23 extending through apertures l8 thereof. Pipes 23 penetrate hangers I through apertures thereof giving substantial clearance about the pipes and are supported on the hangers through strips 24 of any suitable insulating material such as mycalex. Strips 24 are fastened to hangers I5 by means of brass bolts 25. Brass washers 26 are inserted between strips 24 and hangers I5 for increasing the creeping distance between pipes 23 and hangers I5 over the surface of strips 24.

Brass bushings 21 surrounding pipes 23 are interleaved between plates I'I, 2| for determining their spacing. A. plurality of nuts 28 associated with the usual spring washers 29 are screwed on pipes 23 for pressing plates II, 2| and bushings 2! securely together in electrically conductive relation regardless of temperature variations of the capacitor.

Four of bushings 21 are each provided with an annular slot 3|) wherein the suitably shaped end of a copper strap 3| is inserted and brazed to form a terminal connection. Straps 3| are joint- 7 between plates I! but are rotated by ninety degrees with respect thereto.

Plates 36 are insulated from the adjacent plates I! by the dielectric confined therebetween, which may be supplemented by plates of solid insulating material.

Plates 36 are supported on one or more horizontal copper pipes 39 extending through apertures 31 and rest on the pipes in thermally conductive relation therewith through the edges of such apertures. Pipes 39 penetrate with small clearance through apertures of hangers I5 and rest directly on the edges of such apertures.

Brass bushings 4| surrounding ipes 39 and resting thereon in thermally conductive relation therewith are interleaved between pl tes 36 for determining the spacing of each plate 36 with respect to the adjacent plates 36 and also with respect to the plates l interleaved therebetween. The outside diameter of bushings 4| is so chosen that the bushings are in the required spaced relation with respect to the edges of indentations IQ of plates l1, and bushings 21 likewise are in the desired spaced relation with respect to the edges of indentations 38 of plates 36.

The lower pair of pipes 39 is associated with a pair of bifurcated copper terminal straps 42 for conducting current to plates 36 from a pair of co per terminal bolts 43 mounted on cover I2. The lower ends of straps 42 are drilled and encompass the associated pipes 39. A plurality of nuts 44 with associated spring washers 45 are screwed on pipes 39 for pressing together hangers I5, plates 36, bushings 4| and. in the case of the lower pipes, straps 42 in thermally and electrically conductive relation. Current is thus conducted between terminals 43 and plates 36 independently of bolts I6, which support the weight of the entire plate assembly and therefore cannot be depended on to provide a low resistance connection between cover I2 and hangers I5.

For cooling the capacitor the diiferent pipes 39 are connected hydraulically in series with each other and with a suitable source of water or other cooling fiuid under pressure (not shown) through a plurality of copper pipe sections 46 to 50. Each pipe section comprises a rectilinear portion and at least one elbowed portion ending in alinement with the cooperating pipe 39. As shown in Fig. 7, each pipe section is inserted within the end of the cooperating pipe 39, preferably with a tight fit, and a body of silver solder 5| or other fusible metal is provided for uniting the cooperating pipe ends in pressure tight relation. Pipe sections 46 and 59 extend through cover I2 and are soldered thereto. Pipe sections 46 and 50 may be provided with drilled flanges 52, 53 for fastening them to a framework, and may also be provided with compression type fittings 54, 55 for connecting them to the source of cooling fluid and to a drain.

It will be apparent that the herein described capacitor is a simple construction and involves a minimum number of different parts. In particular, the parallelepipedic form of the casing permits its easy fabrication and causes the ca.- pacitor to occupy a minimum of space. The plates may all be made from sheet metal by means of a single die, subject only to the further provision of indentations 22 in the two plates 2|. The plates are held in good thermally and electrically conductive connection with the other plates and with the intervening bushings by means of the nuts and spring washers provided therefor.

In operation, heat is evolved mainly in the portion of dielectric I4 confined between plates I'l, 2| and plates 36. The heat is easily transmitted to plates 36 and bushings 4| by conduction and convection. Plates 36 and bushings 4|. being of substantial thickness and in direct contact with pipes 39, transmit the heat thereto by conduction without substantial temperature drop. The fluid flowing through pipes 39 removes the heat from the pipes whereby the hot spot temperature of dielectric I4 may be maintained within a few degrees of the temperature of the fluid supplied to pipes 39.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claim.

It is claimed and desired to secure by Letters Patent:

A capacitor comprising a casing, a dielectric in said casing, a plurality of suspension hangers, a plurality of bodies of insulating material, means for mounting said insulating bodies on said hangers. a plurality of substantially square metallic plates all provided with a plurality of circular apertures and of indentations of substantially larger size than said apertures and divided into a first plurality of said plates immersed in said dielectric and a second plurality of said plates interleaved with said first plurality of plates, the end plates of said first plurality of plates being provided with. additional oppositely disposed marginal indentations to provide clearance for the said mounting means, means for supporting said first plates on said insulating bodies comprising a first plurality of supporting pipes extending througth the said apertures of said first plates and through the indentations of said second plates, a first plurality of metallic bushings surrounding said first supporting pipes and interleaved between said first plates in spaced relation to the edges of said second plates, and means for pressing and maintaining said first plates, said first bushings and said first supporting pipes together in substantially constant electrically conductive relation regardless of dimensional changes of said first supporting pipes caused by temperature variations of said first supporting pipes including a first plurality of nuts and spring washers on said first supporting pipes, means for supporting said second plates on said hangers comprising a second plurality of supporting pipes extending through the said apertures of said second plates and through the said indentations of said first plates, a second plurality of metallic bushings surrounding said second supporting pipes and interleaved between said second plates in spaced relation to the edges of said first plates, and means for pressing and maintaining said second plates, said second bushings and said second supporting pipes together in substantially constant thermally and electrically conductive relation regardless of dimensional changes of said second supporting pipes caused by temperature variations of said second supporting pipes including a second plurality of nuts and spring washers on said second supporting pipes, and means for cooling said dielectric comprising a source of cooling fluid, a pipe section ex- 6 tending through said casing for connecting one of said second supporting pipes with said source, another pipe section extending through said casing to serve as an outlet for another of said second supporting pipes, and at least one pipe section interconnecting said second supporting pipes for causing a flow of cooling fluid from said source through the difierent said second supporting pipes, said pipe sections being immersed in said dielectric to cooperate with said second plates and said second supporting pipes in transmitting heat from said dielectric to said cooling fiuid.

HERMAN C. DUSTMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,955,776 Smith Apr. 24, 1934 2,079,921 Osnos May 11, 1937 2,151,787 Marbury Mar. 28, 1939 FOREIGN PATENTS Number Country Date 395,420 Great Britain July 20, 1933 

